The present invention relates to a valve arrangement for a medical apparatus for stopping fluid passage through a flexible tubing.
A prior art valve arrangement for a medical apparatus of the kind as herein referred is described in U.S. Pat. No. 4,960,259. This known valve arrangement is intended for being used with an infusion device and comprises a stepped bore into a larger diameter of which a portion of a flexible tubing is inserted. An infusion cannula is arranged for being axially projected from one end of the stepped bore having the larger diameter to its opposite end having the smaller diameter for being inserted into a catheter tube which is taken up by this smaller diameter of the stepped bore. For allowing a fluid passage through the associated portion of the flexible tubing which is axially aligned with the associated end of the catheter tube and the associated end of the infusion cannula the flexible tubing must first be released from a radially directed pressure of a press member which in a protruded active relative position normally squeezes the flexible tubing at an intermediate position for stopping fluid passage through the flexible tubing. The press member is guided by a radial bore of a radially extending neck portion of a valve housing incorporating the stepped bore and may be moved by means of a screw connection into a retracted inactive relative position in which pressure is released from the flexible tubing and therefore fluid passage through the infusion cannula when inserted into the catheter tube will be allowed.
German Patent DE 690 07 003 T2 discloses a valve arrangement which is intended for being used with a linear peristalsis pump. A flexible tubing is connected with a fluid reservoir and is passed through a housing for being alternately squeezed in a first position and in a second position by a series of pump fingers for obtaining a displacement of the fluid which is captured in the flexible tubing when the pump fingers are alternately retracted into an inactive relative position for releasing their pressure on the flexible tubing. The pump fingers are moved by a corresponding number of control curves of a camshaft which is rotateably supported in a longitudinal bore of the housing. The longitudinal bore extends parallel to the portion of the flexible tubing which is passed through the housing. The pump fingers will therefore be moved by the associated control curves of the camshaft between a protruded active relative position for squeezing the flexible tube and a retracted inactive relative position for allowing a delivery of the fluid through the associated portion of the flexible tubing.
An object of the present invention is to provide a valve arrangement of the kind as above referred which may be enlarged in a simple manner for also allowing a control of a fluid passage through at least a second flexible tubing which is connected with the same or with a different medical apparatus for being alternately supplied with the same fluid or with different fluids.
The present invention accordingly provides a valve arrangement for a medical apparatus for stopping fluid passage through a flexible tubing which is characterised by the features as outlined in the claims.
A valve arrangement in accordance with the present invention therefore provides a rather simple measure for allowing an enlargement by the provision that the flexible tubing is passed through the valve housing in a direction normal with respect to the longitudinal bore rotatably supporting the camshaft and also normal with respect to the moving direction of the press member. With the provision of at least a second press member at an axially offset position of the camshaft fluid passage through at least a second flexible tubing which will be arranged side-by-side with a first flexible tubing may therefore be controlled by an associated second control cam of the camshaft. Such a multiple control of a fluid passage through multiple flexible tubings is further simplified by a design of each control cam as a sink of the otherwise circular surface of the camshaft so that when an associated press member radially aligned with such a sink the same will determine a retracted inactive relative position of the press member for allowing fluid passage through the associated portion of a flexible tubing. The press member will on the other hand be moved into a protruded active relative position by the closed circular surface of the camshaft for then squeezing the associated portion of a flexible tubing and for stopping fluid passage.
Other objects, features and advantages of the present invention will become apparent from reading the following description of a preferred embodiment of a valve arrangement according to the present invention.